1. Field of the Invention
The present invention relates to a mobile apparatus or machine combination for sequentially exchanging selected consecutive groups of old ties in an existing railroad track, for example every third or fourth tie of the track or groups of, say, three adjacent old ties, for groups of new ties while retaining groups of, say, three adjacent old ties therebetween to support the mobile apparatus on the track, by means of a succession of different individual devices operatively coordinated to effectuate different sequential operations for exchanging the selected old ties for the new ties. Preferably, this apparatus is combined with a train for loading, transporting and unloading the ties on, in and from open top railroad cars.
2. Description of the Prior Art
U.S. Pat. No. 4,253,398, dated Mar. 3, 1981, discloses a mobile apparatus for the continuous sequential replacement of all old ties of a track with a track renewal train which removes the old ties and lays the new ties while the track rails are lifted and spread apart.
U.S. Pat. No. 4,611,541, dated Sept. 16, 1986, discloses a continuously advancing ballast cleaning machine with tie replacement devices, wherein the ballast is excavated, cleaned and returned while the track is raised a substantial amount. The tie pulling and inserting devices are mounted between the swivel trucks supporting the respective ends of the ballast cleaning machine frame and are connected to longitudinal displacement drives. These devices are used only when an obstacle hindering the operation of the ballast excavating chain is encountered on the shoulder of the track, i.e. they are merely auxiliary means in the ballast cleaning machine for occasional use. No control or control cab for operation of the auxiliary tie replacement devices is indicated.
U.S. Pat. No. 4,301,738, dated Nov. 24, 1981, discloses an apparatus for the replacement of track rails, which comprises two successive work vehicles with projecting, cantilevered machine frame portions. The leading work vehicle carries longitudinally displaceable tools for pulling spikes and devices for lifting and spreading the rails as well as a vertically adjustable receptacle, including a magnetic drum, for the pulled spikes. The trailing work vehicle carries a crib broom, a device for placing and inserting tie plates and a tool for driving the spikes into the ties. The machine has no means for replacing some or all of the ties.
German patent No. 2,230,202, of Aug. 16, 1973, discloses a device for clearing ballast from a track bed. This ballast removing device or scarifier comprises plate-shaped ballast clearing and planing tools which are vertically and laterally adjustably mounted on a cantilevered front portion of the machine frame. The ballast removing plates are preceded by a longitudinally displaceable push rod which may be driven to push a respective tie whose fastening elements have been slightly loosened to enable the ballast removing plates to push the ballast under the displaced tie towards the track shoulder.
It is also known, and has been widely practiced, to exchange only groups of ties in an existing track, for example every third or fourth tie or groups of adjacent ties between ties retained in the track to enable the same to support rolling stock traveling thereover, which is the technology to which the present invention relates. Such a partial tie exchange or renewal is repeated every few years until all the ties of the track have been replaced. Such a mechanized tie gang has been described on pages 22 to 24 of "Railway Track and Structures", November 1983. This mechanized tie gang comprises up to 24 pieces of equipment, such as tie cranes, spike pullers, tie shears, tie cranes for handling tie butts, rotary scarifiers, tie injectors, tampers, rail lifts, spikers and ballast regulators. In the operation of this tie gang, the old ties are withdrawn and placed on the shoulders of the track after optionally being sawn into chunks and they are then loaded onto railroad cars. The new ties are placed on the track shoulders for insertion. The loading and unloading of the ties may be effected at a different time than the tie exchange operation.
The mobile tie exchange apparatus comprises a succession of coordinated and different individual devices operative to effectuate different sequential operations for exchanging the selected ties, such as tie exchange operating devices equipped for pulling spikes, removing old tie plates, withdrawing old ties, scarifying the ballast, inserting new ties, placing new tie plates and driving new spikes. These tie exchange operating devices are suitably spaced from each other in the direction of the railroad track for coordinated operation. Some of such devices are shown in the September 1985 issue of "Railway Track and Structures", including the tie remover/inserter described and illustrated on pages 49 and 64, the self-propelled tie saw on page 58, the spike puller and hydraulic track lifter on page 61, the mechanized plate handling machine on page 66, the anchor tightening machine on page 105, and the spike setter-driver on page 106. Each of these machines are individually operated, self-propelled devices having their own undercarriages for supporting them on the railroad track.
In addition to the above-mentioned mechanized tie gang, other tie-renewal gangs are described on pages 28, 29 and 31 of "Railway Track and Structures", June 1978, and on pages 14 to 16 of the December 1968 issue of this publication. All of these known mechanized tie gangs are comprised of varying numbers of some 14 to 24 individual self-propelled machines, operating personnel being stationed between some of these machines for effectuating additionally required operating steps. The exchange of every third or fourth tie is effected with these known mechanized tie gangs by first removing the tie clips or anchors from the track, then pulling the spikes, removing the old tie plates, withdrawing every third or fourth tie, optionally sawing the withdrawn tie into chunks, placing the withdrawn ties or tie chunks on the track shoulder, scarifying the ballast, i.e. excavating it, in the areas of the track bed which supported the withdrawn ties, inserting new ties in these scarified track bed areas, the new ties having been conveyed to, or stored on, the track shoulder laterally adjacent these areas, whereupon new tie plates are inserted between the inserted new ties and the slightly raised railroad track rails, the new ties are tamped, new spikes are driven into the new ties to fasten the rails thereto, and the tie clips or anchors are applied again. In this connection, an independently operating tie plate distributor car, such as described and illustrated on pages 93 and 94 of "Progressive Railroading", March 1984, may be used for transporting and storing the old and new tie plates.
A tie renewal operation with the individual machines hereinabove described does not only require a large number of operators, including control and monitoring personnel, but also blocks long track sections and their neighboring tracks for a long time so that train traffic is interrupted for extended periods. The efficiency is low because it is exceedingly difficult to coordinate the operation of the many individual machines which are spaced from each other along the railroad track, causing numerous interruptions in the operation. In addition, if an attempt is made to pass some trains on a neighboring track even at low speed, the operators are exposed to danger. The mechanized tie gangs of the prior art, as exemplified hereinabove, does not produce accurate work since it is often difficult, if not impossible, properly to coordinate the operation of the individual machines and to align them exactly with the track line and level for their designated work.
Commonly assigned U.S. patent applications Ser. Nos. 97,757, 97,759 and 97,760, all filed Sept. 17, 1987, disclose a mobile tie replacement apparatus which comprises at least one elongated bridge-like work vehicle having two undercarriages supporting respective opposite ends of the work vehicle on the railroad track, and a succession of different individual devices mounted on the work vehicle or vehicles between the undercarriages and operative to effectuate different sequential operations for exchanging the selected old ties for the new ties. The present invention provides specific improvements in such an apparatus.
U.S. Pat. Nos. 4,175,902, dated Nov. 27, 1979, and No. 4,190,394, dated Feb. 26, 1980, disclose an apparatus and method for loading and unloading open top or gondola railroad cars for transport of the ties used in such a tie exchange operation. The apparatus comprises a train mounted for mobility along the railroad track and includes a plurality of the open top railroad cars having a considerable loading volume, adjacent ones of the railroad cars being coupled together and each railroad car having two high parallel side walls with top edges and two high end walls, the end walls of the adjacent railroad cars defining respective gaps therebetween, and a power-driven crane with booms for loading and unloading the ties and having two undercarriages supporting the crane for mobility in the direction of the railroad track. The undercarriages have pneumatic tires to enable the crane to be moved along a road or the railroad track, and the crane also has pivoted gliding feet or brackets for gripping the top edges, the relatively widely spaced top edges of the railroad cars serving as a track for moving the crane along the cars while the gliding feet grip the top edges. A cable is attached to the crane to pull the crane along the railroad cars as it is perched atop the cars. Operation of this apparatus requires great skill and a number of sometimes life-threatening manual steps. The movement of the crane between adjacent cars is particularly difficult and very time-consuming, which considerably reduces the efficiency of the operation. The crane movement along and between the cars is quite unstable, providing unsafe operating conditions and frequent interruptions. In addition, the tractor used for the crane must be specially designed to enable the crane to effectuate the required forward and rearward movements on the top edges of the gondola cars.
The old and new ties may be loaded, transported and unloaded at the same time or another time by a mobile loader and unloader installation of the first-described type. After the tie exchange has been completed, the ballast supporting the track may be regulated and shaped, and the track ties may be tamped, with a concomitant track correction, for example by means of a track tamping, leveling and lining machine of the type disclosed in U. S. Pat. No. 4,534,295, dated Aug. 13, 1985.